Apparatus for making heat sealed ruffled articles



Jan. 191954 L. c. HosFlELD APPARATUS FOR MAKING HEAT SEALED RUFFLEDARTICLES Original Filed Dec. '7, 1946 3 Sheets-Sheet l lNvENToR LEE C.HOSFIELD ATTORNEY L. C. HOSFIELD Jan. 19, 1954 APPARATUS FOR MAKING HEATSEALED RUF'FLED ARTICLES Original Filed Deo. 7, 1946 3 Sheets-Sheet 2lNvENToR LEE C. HOSFIELD BY Jan. 19, 1954 l.. c. HosFlELD APPARATUS FORMAKING'HEAT SEALED RUFFLED ARTICLES Original Filed Dec. 7, 1946 3Sheets-Sheet 3 Moveable 'horz'fzg Slug xNvEN-rofz LEE C. HOSFIELDPatented Jan. 19, 1954 UNITED STATES aan ATENT OFFICE APPARATUS FORMAKING HEAT SEALED RUFFLED ARTICLES Lee Hoseld, Parma, Ohio, assigner,by mesne assignments, to Union Carbide and Carbon Corporation, acorporation of New York Claims. (Cl. 154-15) This invention relates tonovel unitary heatsealed ruies and rullied articles made fromthermoplastic dielectric materials, and to a novel process and apparatusfor making such unitary rufiies by spot-welding together succesivefoldedover portions of ruined films, sheets, fabrics or other sheet-likeelements of thermoplastic dielectric materials and, if desired,concurrently spot-welding successive folded-over portions of the latterarticles to another sheet, lm, fabric or other sheet-like element madefrom the same or another thermoplastic dielectric material.

A large variety of articles such as raincoats, aprons, umbrellas, windowcurtains, shower curtains, dry goods Sundries and the like now are beingmade from thermoplastic resinous dielectric materials. In themanufacture of such articles it is common practice to unite the marginsof two or more lms by sewing the margins together, using thread ofsuitable material. Such operations involve the repeated puncturing ofthe sheeting by the fabricating needles at closely-spaced points,thereby weakening the material at and adjacent the seam. Moreover, theseam produced is stiff and incapable of yielding when subjected tostretching forces, so that sudden stresses sometimes tear the threadfrom thesheeting or break the thread after only a slight elongation ofthe lms. This method of fabrication is not satisfactory, particularlyfor articles where strength, durability, or imperviousness to water orother liquids and gases are required.

For the purpose of providing a stronger article, processes have beendeveloped whereby sheets or lms to be united have flat overlappingmargins pressed together to form a seam while being heated to suitabletemperatures. Heat and pressure are applied by means of heatedcooperating pressure rolls to form a continuous welded seam.

In recent years the so-called electronic method of heating has assumedimportance as a source of the welding heat. Opposed pressure rolls serveas rotating electrodes in a high frequency electric circuit. Thethermoplastic dielectric materials, while continuously pressed betweenthe electrodes, are subjected to a high frequency electric field,thereby being softened and welded together. Continuous narrow weldedareas which readily are visible are thus formed. Such methods reduirethat the sheets to be united are of uniform thickness and free fromwrinkles, etc.

There are a wide variety of articles made from thermoplastic dielectricmaterials which, to be satisfactory for the intended use, require theaixing to a sheet, film or fabric made of or containing a coating of athermoplastic dielectric material, of ruffles of the saine or anequivalent material. Among such articles may be mentioned windowcurtains, shower curtains, aprons and other articles of wearing apparel,shelf and table decorative strips and covers, and the like. fijnere alsois a demand for unitary ruilled articles made from such dielectricmaterials.

lt is highly important that such ruilled articles have an attractiveappearance and be of a uniform construction. The ruffled structure mustbe strong, tough, permanent, and sufliciently elastic to yield whensubjected/to tensile or to puncturing forces without being injured ordestroyed. The present invention is concerned with such a ruied articleand with the novel method and apparatus for its production.

Among the more important objects of the invention are the following: toprovide a novel unitary ruffled article made entirely of thermoplasticdielectric material; to provide an unperforated heat-sealed ruffle orruied article of dielectric material, and one which is free fromrestricting threads of dissimilar material; to provide a ruffled articlewherein the sides of each ruffled area formed in a dielectricthermoplastic material are permanently united to each other and to anadjacent ruffled area, and, if desired, to a base sheet, by a pluralityof spot welds to provide a rui'lied composite article wherein eachindividual fold of the ruie is of uniform size and is spot welded to thebase sheet and to an ad- `iacent fold at one or more spaced points oflimited area; to provide such a unitary heatsealed ruffled article whichcan be elongated more than of its original length without rupturing theruffled structure or the seam; to provide heat-sealed ruiiles havingstronger bonds between the base sheet and the ruffle and greaterresilience along the line of the -ruie than ruled articles made bysewing with thread; to provide novel ruiled articles wherein repairs tothe ruiiles can be made merely by spot-welding without loss of theruilied material; to provide in novel manner for the production at highrates of thermoplastic sheet-like articles having permanently unitedtherewith strong welded-on ruliies, uniform and pleasing in appearance,and having good physical properties; to provide a novel process andapparatus for continuously producing thermoplastic articles havingwelded-on ruiles whlle preventing injury to the ruied material' toprovide a novel process and apparatus for weldmg rules of a dielectricmaterial upon a 3 base sheet of such a material by means of a highfrequency electric field, while inhibiting arcingr at the electrodes andburning of the material; and to provide in novel manner for thecontinuous spot-uniting of ruffled sheets, films, fabrics or the lilremade from or containingr dielectric thermoplastic materials with othersheets, films, or fabrics made from or containing the same or otherthermoplastic dielectric material, either plasticized or unplasticized,ormade fromxpaper,l

cloth and like materials coated with such a dielectric material.

The invv-ntion especial utility for the production of strong, permanent,yielding ruf'les and ruffled articles having elastic properties madefrom such plasticized thermoplastic. materials as the cellulose estersand ethers, such as cellulose acetate, viscose, regenerated celluloseand ethyl cellulose; vinyl resins, such as the polyfvinyl chlorides, thepolyvinyl acetates, copolymers of vinyl chloride and` vinyl acetate,polyvinylidene chloride resins, polyvinyl alcohol resins, polyvinylacetal resins, polymethacrylate resins, and copolymers of vinyl halidesand acrylic compounds, such as copolymers of vinyl chloride withacrylonitrile, with acrylic acid, and with the acrylic acid lower alkylesters; copolymers of butadiene with styrene and with acrylonitrile;resinous reaction products of a diamine and a dicarboxylic acid.

A preferred form of the novel articles of the invention generallyinvolves a base sheet, silk, fabric or other sheet-like element of atlrermon plastic synthetic resin or other dielectric material which ispermanently united by one or more series of spaced spot welds with asheetlike element of the same or other thermoplastic dielectric materialhaving the form of a continuous succession of interconnected folds orruillcg of uniform size and shape. The respective sides of each foldedaree, are permanently united with cach other, with a side of the nextadjacent.

folded area, and with one or more layers of the base sheet by means ofatleast one spot weld, and preferably two welds, covering a smallportion of eachsuch folded area. Since the individual folds are notsecured by restricting non-elastic sea/ed threads, the entire body ofthe welded rutile or the composite article is free to yield undertension andto elongate or stretch, the extent of such elong tion boingdependent upon the character the material from which the sheetlikeelements are made, the number, area and character of the spot Welds,upon other factors. In the case of articles made from sheets of vinylresins, such as those produced by the copolymerisation oi a vinyl halidewith a vinyl ester of a lower aliphatic acidwe. g., a vinylchloride-vinyl acetate copolymer containing between '70% and 95% of thechloride in the polymer--the heat-sealed ruffled article can beelongated more than 90% of its original length without rupturing thewelded seam and, when tension i5 released, will regain its originallength. The bond between the base sheet and the ruiiled sheet is from GGto 99 et stronger than that secured in the same article by sewing withthread.

Since each of the folds is unrestricted by. threads, the peak of eachfold is free to pucirer outwardly from the base sheet and to give to theruiiled article aA uniform, pleasing appearance. The folded areas arenot noticeably deformed by the welding heat and pressure used.

lf, when such a ruffled article is subjected to excessive stress, one ormore of the spot welds fl fails, the ruffles still are held in place andthe appearance and the strength of the ruffled structure are preservedby the remaining7 spot welds adjacent those which failed.

The novel ruffled articles are made, in accordance with a preferred formof this invention, by a novel process and apparatus which forms a rapidsuccession of similar rufiies or folds of the desired size and shape ina sheet-like element of suitable dielectric material and, as rapidly aseach such ruffle or fold is formed, the sides of such fold arepermanently spot-welded to each other and to a surface of a nextadjacent fold., and preferably toY one or more layers of a suitablesheet-likebase element, at from one or two or more spaced points oflimited area in such fold. The Welding is effected by the use oflocalized heat and pressure. The heat is produced locally in thematerial at each successive folded area by bringing such areas betweentwo electrodes to which a. high frequency electric c rrent of suitablevoltageis applied, as hereinafter more particularly described.

In the accompanyingT drawings wherein are illustrated certain preferredforms of the invention,

Fig. 1 is a diagrammatic view of one form of apparatus of the invention,parts being omitted;

Fig. 2 is a side elevation of one form of heatsealing machine showingthe electrodes, electrode reciprocating mechanism, and associated parts,parts being broken away, and other parts being omitted;

Fig. 3 is a schematic wiring diagram of another high frequency heatingcircuit and associated parts;

Fig. 4- shows diagrammatically the relationship between the actuatingcam` for theV reciprocating electrodeand the rotary tuning device ofFig. 3;

Fig. 5 illustrates two alternate forms oi' tuning stubs or impedancematching means for the high frequency heating circuit;

Fig. 6 is a fragmentary plan view of a folding and indexing blade forforming Vthe ruffles;

Fig. 7 is a perspective fragmentary view of a reciprocatable electrodeand operating stem;

Fig. 81 shows one preferredA form of. ruiled; com,- posit'e article ofthe invention;

Fig. 9 shows another form of the ruiiled composite article;

Fig. I0 shows a unitary ruilled heat-sealed strip reinforced by afolded-over end margin; and

Figs.. 11' and l2, respectively, show other forms of composite rufliedarticles of the invention.

Referring toFigs. 1 and 2 of the drawings, the4 apparatus comprises anoperating head H which conveniently may be mounted on a table T,generally similar to the operating head and table of the standard typeof sewing machine. Secured to the lower endv of va member I I mounted onthe head H for longitudinal recprocation are one or more upperelectrodes I3 adapted to cooperate with corresponding stationary lowerelectrodes I5 aligned therewith and formed on an electrode plate IB-secured below the table top in suitable manner and insulated from thelatter by a plate I1 of a dielectric material such as polystyrene; Arider I8 secured to member I I slides in a groove in a guide member I2and prevents turning of the member I I.

For passing a high frequency electric current through a plurality oflayers of one or more-sheets.

of thermoplastic organic dielectric material while in the space betweenthe electrodes to heat such material to a welding temperature, theelectrodes are in a high frequency electric circuit which comprises anoscillator or generator I9 or other source of high frequency electriccurrent. One terminal of the high frequency output line is groundedthrough a line 2i). The other terminal is connected with the stationaryelectrode plate iii through a coaxial transmission line, the outerconductor ila of which terminates in the outer tube 23 of a tuning stub26 such as shown in Fig. 5. The inner conductor 2| terminates in acoaxial inner rod 23a of the stub 25. A coaxial variable capacitance 24connects the tube 23 and rod rita within the said tube. Tube 23 isgrounded through line 25. A short circuiting member 26a fixes the lengthof the short circuited stub. The electrode i3 is grounded through aflexible strap 2l.

For reciprocating each electrode I3 in a iixed path toward and from acorresponding stationary electrode l5, a standard electric motor 29,equipped with a magnetic brake for instantaneous starting and stoppingand of a type oommonly used on industrial sewing machines, drives arotatable shaft BI through pulleys 33 and 35 and V-belt Si. Shaft 3|drives an upper shaft 39 through pairs of beveled gears 49, 49, and 4I,lil, and vertical shaft 43. Secured upon one end of shaft $9 is a camplate 45 having a groove in one face providing a cam surface 41. A camfollower ad is mounted for rotation on a pin secured upon a followerblock I. The latter is secured for vertical adjustment uponreciprocatab-le rod II and has rigidly connected therewith the electrodeor electrodes I3. By means of a set screw E2 in block 5I the latter canbe secured at a selected point along the rod II and thus determine thepressure applied upon the thermoplastic material by each electrode I3when the latter is in the lowermost position during a spot-weldingoperation. A compression spring 53, operatively interposed between a pinor flange on rod Il and a fixed part of the operating head H,continuously exerts a downward pressure upon the reciprocating rodduring operation and prevents backlash.

For feeding a strip or sheet of dielectric material M from a source ofsupply thereof and for forming a succession or ruliles or folds thereinadjacent the welding or heat-sealing zone a pair of feeder rollsincluding an idler roll 55 and a roll 5E driven by a motor 51 draw asheet of such material from a supply roll 58. The sheet then is directedaround a dancer roll BI and idler rolls 62, 62 and 52 and thence betweena xed margin fold-over guide 63. It then is moved intermittently to thewelding zone between the electrodes i3, i5, by means of a ruiflingmechanism R. The dancer roll 6i is rotatably mounted upon an end of arod 59 which is pivoted about a fulcrum td. Mounted on the end of rod 59opposite roll Sil is an adjustable counterweight, and a mercury switch84 of Well-known type having terminals connected in the electricalcircuit driving motor 5l'. The arrangement is such that when the roll Siis in the position shown in full lines in Fig. 1, the switch 64 cuts oifcurrent to motor di, and that when roll 6I is in the position shown inbroken lines the switch closes the circuit and drives motor 51. Thus,any diiferences between the rate of unwinding of material from thesupply roll and the rate demands of the ruffling mechanism areequalized.

For feeding a sheet M, with or without a base sheet or lm B, ofthermoplastic dielectric material between and past the electrodes at awelding or heat-sealing zone, a resiliently mounted presser foot @lcooperates with a vertically and laterally movable feed dog 'de whilepressingly engaging the sheets interposed therebetween. The feed dog hasa serrated surface area adapted intermittently to contact the undersideof the ruffled sheet or the composite sheet B and move the same to theleft in Fig. 1 away from the welding zone. Thereafter the feed dog isdepressed and withdrawn from contact with such sheet and moved to theright toward the Welding Zone. For effecting such feed of the sheet orsheets the presser foot El is secured to a rod 6B mounted on the head Hfor movement toward and from the feed dog E55. An adjustable compressionspring 'it presses the foot El upon the sheets lying upon the feed dogunder a selected pressure. A cam member 'il pivoted on the head Hcooperates with a member i2 secured to rod 53 for raising and loweringthe rod t8 and for locking it in raised position. For effectingintermittent movement of the feed `dog and the sheets lying between itand the presser foot in a direction from the welding zone, as showndiagrammatically in Fig. l, the feed dog ESS is secured to an arm '13which is connected with a crank i4 secu-red upon the shaft 3L The crankarm 'Iii is pivoted upon an end of a rocker arm l5, the other end ofwhich is pivotally connected with a xed support. In the form shown inFig. 2, the feed dog is secured to a plate 'ifi which has an endpivotally secured to the arm '15. A cam member Ti mounted on shaft 3lcooperates with a cam groove in the plate l5 during rotation of theshaft. The cam member is pivotally connected with arm *1:3 through armi3. During operation of motor 29 the rotation of shaft 3! and crank i4causes the feed dog 59 successively (l) to rise vertically and engagethe sheet M or B, (2) to move to the left to index the ruiiled article,then (3) to retract downwardlj,7 from the sheet and (4,) to move towardthe right while disengaged from the latter; and to repeat this cycle ofmotions for every rotation of shaft 3|. The movement of feed dog Se istimed so that it advances the ruflied article to the left a selecteddistance just before each forward movement of the foldindexing mechanismto be described.

For forming in sheet M a succession of rufes of uniform size and spacingat a uniform rapid rate, a crank plate 79 secured upon shaft 3e isoperatively connected, by means of a rod 8@ and a clevis Iii with alever arm 32 secured upon a rocker shaft 83 suitably supported on theoperating head. When shaft 39 is rotated the rocker shaft 83 oscillatesthrough a selected arc, depending upon the position of clevis iii alongthe arm 82 maintained by means of a clevis pin cooperating with one ofthe apertures in arm 82. Secured to an-end of rocker shaft 83 is a leverarm 84 which supports an adjustable folding and indexing blade d5. Thelatter is pivoted upon ears formed on the lever arm 94, and has a rearflange portion cooperating with a spring 85 carried by that arm to urgethe blade 85 downwardly against the sheet of material under a regulatedtension. The forward end of the blade has a serrated margin and hastherein slots Si (see Fig. 6) adapted to accommodate the eleotrodes I3,I3. The arrangement is such that blade 85 is held in retracted positionto the right (see Fig. 2) away from the electrodes i3 during the weldingpart of each cycle of operation, and

then advances .to the left during thepart of the cycle when electrodesI3, I are held apart, thereby moving fresh sheet material into positionbetween the spaced electrodes and forming therein a fold or pleat. Astationary serrated blade 85 prevents retraction of the sheet M whenblade 35 is retracted, and prevents folds being formed in sheet B. Afolder guide 63 adjacent the folder guide 63 folds over a margin of thebase sheet as it moves to the welding zone.

The fold or pleat produced can be varied in size, and the number offolds or pleats per inch can be regulated, by the adjustment of thelength of stroke of the arm 84. To increase or to reduce the number offolds per inch, clevis 8| is connected with arm 82 at a point furtherfrom or nearer to shaft 83, respectively. Preferably the adjustment issuch that from six to eight rules or folds per inch are produced,although articles having from four to twelve folds per inch readily aremade. However, the ruflled areas should be at least one-sixteenth of aninch in width in order to insure the spot-welding of each rule at one ormore spaced points even in in stances where some stretching of thematerialresults from action of the folder blade 85 or of the feeder foot59.

The actual welding portion of each cycle of operation, during which theelectrodes I3, I5, or respective pairs thereof, exert pressure upon thefolded-over portions'of the ruffle material, .and upon the base sheetwhen present, constitutes about three-fourths of the cycle and isgoverned by the shape of the cam surface 41. The welding of the ruffledarticle is accomplished during this time by passing through the layersof material at the spot-welding zone between the electrodes a highfrequency current of from to 500 megacycles and at suitable voltages, e.g., around 1,000 volts at 60 megacycles.

In the form of the invention illustrated in Fig. 1 using frequencies of50 to 500 or more megacycles, the tuning stubV 26 of standardconstruction, the variable capacitance 24 and the interconnecting linesdefine a matching circuit having impedance that can be varied toaccommodate various load impedances and to provide maximum powertransfer to the work.

Tuning stubs of the type shown in Fig. 5 are particularly useful asmatching sections when employing frequencies of around 100 to 200 ormore megacycles. Such tuning stubs are in the form of a coaxialtransmission line connected with the high frequency generator. The outerconductor of the coaxial line is a brass tube 90 and the inner conductoris a brass rod 9|. Two brass sleeves 03, 94, serve as terminals of thetransmission line, one sleeve sliding upon the outer conductor 90 andthe other sliding on the inner conductor 9 I. The length of the shortcircuited portion is adjusted by means of a brass disc 95 which slidesalong the inside of the outer tube but also contacts the inner rod 9|.The length of the load end is adjusted by sliding the respectiveterminals 93, 94 along the tubes and rod.

In another form of tuning stub illustrated in Fig. 5, the movableshorting disc 95 is replaced by a fixed shorting disc 96 (shown indotted lines in Fig. 5), so that the length of the short circuited stubis fixed. The points of the transmission line termination at the tubeand rod also are fixed. A coaxial variable capacitance 91 (shown indotted lines) is set within tube 90 and is connected acrosstheconductors 90, 91|.

Fig. 3 illustrates schematically a. form of circuit particularly usefulwithv frequencies of around 50 to 100 megacycles. It effectivelyprevents arcng at each electrode I3 as the latter is rapidly withdrawnfrom the welding zone, by throwing the high frequency circuit out ofresonance from a time just prior to the withdrawal of electrode I3 frompressing contact with the work until after the electrode is in contactwith another ruille in the next succeeding cycle of operation.

If desired, the circuit can be detuned in various ways during suchperiod of each cycle to accomplish this purpose. In the form of theinvention shown in Figs. 3 and 4, the circuit comprises a highfrequencygenerator I9 having one terminalZU grounded and having its otherterminal connected in series through line 22 with a fixed inductance|05, a variable condenser V and the lower electrode plate I6. A line |06having therein a fixed inductance |01 connects line 22 to ground. Thecondenser V has segmental rotor plates 99 subtending an are of 90,mounted upon a rotatable shaft I0!) having an electrically insulatedportion Illa and driven from shaft 3| through a pair of bevel gears I0The condenser has fixed plates 02 `with cutaway segmental portionssomewhat greater than the width of segmental plates 99, andpreferablysubtending an arc of 120. Y

Fig. 4 more clearly indicates the function of the detuning variablecondenser, wherein it is shown in full lines in the position duringwhich a fold is being formed and moved into position between theelectrodes and the high frequency circuit is out of resonance. Oneposition of the plates 99 during the welding stage of each cycle isindicated in broken lines. The use of this condenser permits the use ofoptimum -voltage duringV the welding stage of each cycle, while limitingthe .voltage during the balance of the cycle to one insufficient tocause arcing or burning of the materials.

Fig. l also illustrates the general shape of the rotary cam 41 which, inconjunction with spring 53, controls the reciprocation of rod Ii, andthe period of its dwell in a position with electrode I3 in weldingposition. As shown, this cam and the cam follower 49 raise and lowerelectrode |73 in a vertical patternV during one-fourth of a cycle, andvthen, with the aid `of spring 53, hold the electrode in pressure contactwith the ruffled material during the balance of each'cycle. Throughcorrelation of the timing of the respective `movements of the cam 41,.the folder blade and the feeder foot 59, the successful production ofwelded ruffled articles having eight ruffles per inch, each ruffle beingconcurrently spot-welded in two zones, has ybeen accomplished at therate of 34 feet per minute. This corresponds to the productionof 3,264single welds per minute or, when using two pairs of electrodes, 6,528welds per minute.

In performing the process using the apparatus of Figs. 1 and 2, theleading ends of the respective base sheet B and ruille element M areplaced in mutual contact above the feeder foot 69 and between theelectrodes, and motor 29 is started. The motor concurrently actuates thefeeder foot 69, reciprocates the electrode I3, and oscillates the folderblade 85. Each cycle of operations, during a revolution of cam 41, is asfollows: While electrodes |3 are'raised from the work the presser foot61 cooperates with feed dog 69 and holds the. several thicknessesofsheetswhile the ruiiler blade 85 scuiTs in the ruiile sheet M a foldperpendicular to the direction of feed. Thereafter, while the bladeholds the fold in place the upper electrodes I3 descend upon the foldand hold it, under pressure from spring 53, while the blade B5 isretracted. The radio frequency voitage impressed upon the electrodescauses current to flow through the two walls of each of the one or morelayers of material forming the folded area in sheet M and through eachlayer of the base sheet B, softening the material and spotwelding theseparts together at one or more, and preferably two, small spaced weldingdefined by the electrodes, the degree of welding heat depending upon thevoltage across the electrodes. The electrodes I3 then are rais-ed,thereby releas ing the welding sheets. rIhe feed dog presser foot thenadvance the work to make room at the welding zone for the next ruiile.The parts are so synchronized that the ruier blade 85 is in. retractedposition while the weld is being and that the feed dog te has completedits action advancing each welded ruflie before the rufer blade forms thenext succeeding ruffle.

rlhe apparatus of Figs. 3 and 4 functions similarly to that of Fig. l,with the exception that immediately prior to retraction of theelectrodes I3 from the welding position the high frequency heatingcircuit is detuned by movement of plates 9S of the variable condenser Vinto the position shown in full lines in Fig. 4, thereby reducing thevoltage between the electrodes and preventing arcing at the electrodes.The circuit remains in the detuned condition until the blade 85 hasformed another fold and each electrode i3 has moved into pressingcontact with the upper surface of the newly folded area.

Variations in the rate of application of energy to the material duringthe different stages of each cycle of operations also can be effected bymodulating the oscillator tube in the high frequency generator, or inany other well-known manner.

One preferred form of spot-welded ruiiied article is illustrated in Fig.8. In that figure the two sides Vof each layer of material forming eachof the ruflles or folded areas F in the sheet M, one side of each layerforming an adjacent folded area F, and one or more layers of the basesheet B are permanently united by two spaced spot welds W of anysuitable shape and size. The material at the unwelded portions of eachfolded area is unrestrained and free to assume a rounded shapethroughout the remainder of the length of each fold. All portions of theruflied thermoplastic article are free to yield or stretch under anytension exerted either longitudinally or laterally of the rows of spotweld-.s formed. By employing a folder guide 63 for folding over themargin of sheet M, and/or a folder guide 63 for folding over a margin ofsheet B (see `Eig. l), each spot weld unites from four to six or morethicknesses of the thermoplastic material, as shown in Fig. 8.Preferably, the folded-over marginal portions of both the sheets M and Bare of sufficient depth that each of the welds formed in a rutileunites'the same number of layers of dielectric material as the otherweld or welds.

The tiny but tough spot welds enhance the appearance of the ruiiiedarticle while at the same time providing adequate strength, andpreserving in such article the normal resilience of the thermoplasticmaterial from which the sheeting made, unrestrained by extraneousmaterials haring properties differing therefrom, such as non.-

yielding threads. All portions of each sheet M and B are entirely freefrom perforations and other sources of weakness.

Fig. 9 illustrates a form of the invention wherein each of one or morelayers of a sheet-like element of a dielectric material has formedtherein a succession of closely-spaced folded areas throughout its widthand wherein each of one or more layers of a relatively narrow sheet-likebase of a dielectric material is permanently united with each of saidfolded areas by means of one spot weld located midway between themargins of the reet-like element. By the use of a somewhat widersheet-like base, two or more spot welds can be made in each folded area.By using a sheet-like base and sheet-like element of different colors,attractive color eifects and the effeet of sewing or gathering withcolored threads are secured at each spot weld. Thus, a ruching ordouble-ruffle effect is secured in a unitary article. If desired, two ormore narrow, longitudinally-spaced, sheet-like bases may be united withthe sheet-like element.

Permanent unitary rufes may be made from single sheet-like elements.Thus, in one form of the invention illustrated in Fig. l0, by using onlythe sheeting M, the latter is provided with a ruffled margin whereineach fold is spot-welded in place, the welding uniting the two sides ofeach ruffled or folded area to each other and to a side of an adjacentfolded area. The resultant product may be stored or used as such, orlater may be united with a second sheet or film such as the sheet B, ina separate spot-Welding or other operation.

Fig. 1l illustrates another form of rufe which can be produced inaccordance with the invention. The ruiiies are produced by well-knownfolder attachments now in use on standard sewing machines. Here each ofthe one or more rows of spot welds W unites portions of the sheet lVl atfolded areas through three or more thicknesses of the dielectricmaterial. Each folded area consists of a relatively flat mid-portionlill, two inwardly sloping end portions lll, and two outwardly flaringportions H2, the respective portions being welded together by spacedspot welds arranged in one or more rows. A base sheet B may bespot-welded to the folded sheeting, as in the case of the article shownin Fig. 8.

Fig. l2 illustrates still another form of ruffled article made with theuse of the invention in connection with standard rufliing equipment,l-iere the base sheet B and the ruled sheet M are spotwelded at one ormore spaced points W lying between adjacent ridges.

it will be understood that the invention is not limited to the ruflledarticles specifically described, nor to the particular form of theprocess and apparatus for making the saine described. @n the contrary,numerous modifications are possible within the scope of the appendedclaims, whereby a unitary permanent ruffled article is made, andespecially one wherein the sides of each ruilled area of each of one ormore sheets are spot-welded together and to an adjacent folded area ofsuch sheet at one or more spaced points, and, if desired, to one or morebase sheets, and wherein the remainder of the sheet or sheets at eachruffled area is substantially unconiined and free to yield or stretchunder stress.

Either or both of the sheet-like elements of thermoplastic dielectricmaterial may replaced by a sheet-like element of a non-thermoplasticfibrous material in the form of a woven, knitted,

felted or other fabricV impregnated or coated withr 1 a thermoplasticdielectric material, and the rufs lies formed and spot-welded in themanner hereindescribed. Thus, a woven or knitted fabric made from yarnsof cotton, wool, silk, glass or the like may be impregnated and/orcoated in whole or in part withra film or body of a vvinyl resin orother thermoplastic dielectric material hereinbefore mentioned. Suchcomposite article then is converted into the form of awelded ruffle or,if desired, is concurrently ruilled and secured to another elementof athermoplastic dielectric material or of a non-thermoplastic materialcoated with a thermoplastic dielectric material by welding in the mannerdescribed. Also useful as the sheet-like elements and/or bases are thecomposite fabricsv made from yarns formed by compositing filaments orbers of a non-thermoplastic material such as cotton, etc., withfilaments or iibers of a plasticized thermoplastic dielectric material.

The term sheet-like element and similar eX- pressions used in the claimsare intended to designate sheets, films, webs, batts, and woven, knittedand other fabrics which are relatively small in one dimension.

This application is a division of my pending application, Serial No.714,832, filed December 7, 1946, for an invention entitled Heat SealedArticle and Process and Apparatus for Making Same. now matured as PatentNo. 2,555,409.

I claim:

1. Apparatus for producing-heat-sealed ruffies, which comprises at leastone stationary electrode and at least one cooperating reciprocatableelectrode; means for impressing a high frequency voltage upon saidelectrodes; meansfor intermittently moving successive portions of asheetlike element of a dielectric material between and past saidelectrodes at a selected rate by a rapid succession of short movementsand for discontinuing each such movement; means for moving thereciprocatable electrode at arapid selected rate toward. and from theother electrode and into and out of contact with'the dielectricmaterial; resilient means for pressing the reciprocatable electrode intocontact with dielectric material disposed between the electrodes; meanscorrelating the material-moving means and the electrode-reciprocatingmeans whereby the former is operative when the reciprocatable electrodeis out of contact with the dielectric material; means including aslotted folder arm operatively interconnected with reciprocatableelectrode for forming folds said material; means for reciprocating thefolder arm into and out of the zone between said electrodes; and meanscorrelating the movement of the folder arm with that of thereciprocatable electrode for `moving the former and the material carriedthereby into folding position between the electrodes while thereciprocatable electrode is out of contact with the dielectric materialand for retracting the folder arm from such folding position immediatelyafter the reciprocatable electrode contacts the folded area made in thematerial by such folding movement of the folder arm.

2. Apparatus for producing heat-sealed ruffles, which comprises at leastone stationary electrode and at least one cooperating reciprocatableelectrode; means for impressing a high frequency voltage from a tunedcircuit uponsaid electrodes;

means for intermittently moving successive portions of a sheet-likeelement Aof a dielectric material between said electrodes by' a'rapdSHC-' izfff cession of short. movements and for discontinu-4 ing eachsuch movement; means for moving the reciprocatable electrode at a rapidselected rate toward and from the other electrode and into and out ofcontact with the dielectric material and for maintaining such Contactduring a major portion of each cycle of reciprocation; resilient meansfor pressing the reciprocatable electrode into contact with the materialdisposed between the electrodes; means correlating the materialmovingmeans and the electrode-reciprocating means whereby the former isoperative when the reciprocatable electrode is out of contact with i thedielectric material; means including a slotted folder arm operatively'interconnected with said reciprocatable electrode for forming folds insaid material; means for reciprocating the folder arm into and out ofthe zone between said electrodes; means including a canrmemberassociated with the reciprocatable electrode and a rockable shaftassociated with the folder arm for correlating` the Ymovement of suchelectrode and folder arm for moving the folder `arm and material carriedthereby into folding position between the elecf f trodes while thereciprocatable 'electrode is out of contact with the dielectric materialand forv retracting the folder arm from such folding posiv i tionimmediately after the reciprocatable elecl trode contacts the foldedarea made in the material by such foldingmovement of the folder arm.

3. Apparatus for producing heat-sealed ruffles, which comprises at leastone stationary elec-` s trode and at least one cooperatingreciprocatable electrode; means for impressing a high frequency lvoltage from a tuned circuit upon said electrodes; means forintermittently moving successive por-f tions of a sheet-like element ofa dielectric material between said electrodes by a rapid suc-V f cessionof shortmovements and for discontinuing each such movement; means formoving the reciprocatable electrode at a rapid selected ratev z towardand from the other electrode and into'and out of contact `withthe'dielectric material and for maintaining such contact during a majorportion of each cycle of reciprocation; resilientf means for pressingthe reciprocatable electrode into contact with the material disposedbetween the electrodes; means correlating the materialmoving means andthe electrode-reciprocating means whereby the former is operative whenthe reciprocatable electrode is out of contact with the dielectricmaterial; means including a slotted' folder arm operativelyinterconnected with said reciprocatable electrode for forming folds insaid material; means for reciprocating the folder arm into and out ofthe zone between said electrodes means correlating the movement of thefolder arm with that of the reciprocatable electrode for moving theformer and the dielectric material carried thereby into folding positionbetween the electrodeswhile the reciprocatable electrode is out ofContact with the material and for retracting the folder arm from suchposition immediatetwo electrodes connected in a high frequency' l, tunedelectric circuit for developing welding heat Within' said materia-l atsaid'hea't-'sealingv zone;A

means for reciprocating one of said electrodes into and out of pressingcontact with said material and for maintaining such contact during amajor portion of each cycle of reciprocation; folder means integratedwith said feeder means for forming a succession of folded areas insuccessive portions of said element at said heatsealing zone; and meansinterconnecting and correlating said electrode-reciprocating means andsaid folding means for retracting the latter means from said zone whenthe reciprocatable electrode is in contact with the sheet-like elementand for advancing the folder means into the sealing zone when suchelectrode is positioned remote from said zone.

5. Apparatus for producting heat-sealed ruffies, which comprises atleast one stationary electrode and at least one cooperatingreciprocatable electrode; means for impressing a highfrequency voltageupon said electrodes; means for intermittently moving successiveportions of a sheet-like element of a dielectric material between andpast said electrodes at a selected rate by a rapid succession of shortmovements and for discontinuing each such movement;

means for moving the reciprocatable electrode at l a rapid selected ratetoward and from the said electrode and into and out of contact with thedielectric material, said means including a cam surface cooperating withthe reciprocatable electrode and so constructed that the latter is incontact with the dielectric material for at least two-thirds of eachcycle of reciprocation of such electrode; resilient means for pressingthe reciprocatable electrode into contact with dielectric materialpassed between the electrodes; means correlating the material-movingmeans and the electrode-reciprocating means whereby the forof contactwith the dielectric material and for vretracting the folder arm fromsuch folding position immediately after the reciprocatable electrodecontacts the folded area made in the material by such folding movementof the folder arm.

LEE C. HosFIEL'b.

References Cited in the file 0f this patent UNITED STATES PATENTS NumberName Date 1,249,292 Montgomery Dec. 4, 1917 2,322,298 Johnson June 22,1943 2,427,372 Sigoda Sept. 16, 1947 2,432,412 Hacklander Dec. 9, 19472,477,040 Brown et a1 July 26, 1949 2,484,076 Collins Oct. 11, 19492,490,451 Magid Dec. 6, 1949 2,555,409 Hoseld June 5, 1951 OTHERREFERENCES Hoyler, An Electronic Sewing Machine, reprint from the August1943 issue of Electronics. page 6.

